Tomato is a vegetable crop grown worldwide in all conditions and climates, both in protected cultivation or in open field. Growing tomato plants requires a lot of labor and attention, during which the plants are handled repeatedly by various persons. Handling the plants includes activities such as grafting, planting, pruning, winding, and of course harvesting.
Persons working in a tomato crop rapidly notice that with every contact of a green part of the tomato plant, a green substance comes off on the skin or any surface the contact is made with. The substance can also be yellowish in color. Especially hands and clothes become covered with this substance, which after very intensive handling can result in almost black greenish stains on for example the hands. The main difficulty of this substance is that it is very hard to remove from the skin or clothes by normal washing. The green or yellowish substance results in green staining.
Another aspect of a tomato plant is the typical tomato smell that it emits. This can become rather unpleasant when one is frequently exposed to a tomato crop.
The surface of the various plant parts of tomato (Solanum lycopersicum) is covered with trichomes, both non-glandular and glandular. Non-glandular trichomes are usually regarded as ‘hairs’ and do not produce, store, or secrete specific biochemical compounds.
A variety of biochemical compounds in tomato however are produced in glandular trichomes. A glandular trichome typically consists of a stalk, made up of one or more cells, and one or more glandular cells at the tip of the stalk that form the glandular head. Four different types of glandular trichomes are identified in tomato and related Solanum species, namely types I, IV, VI, and VII. These types differ in size and length of the stalks, and in number of secretory cells that form the glandular head (McDowell et al., Plant Physiology Vol. 155, 524-539 (2011)). The unicellular glands, which may comprise one glandular cell that forms the glandular head, are classified as secreting glands, while multicellular glands are classified as storage glands.
Type VI trichomes are composed of four disc cells, or glandular cells, at the end of a one- or two-celled stalk. The four disc cells form the multicellular glandular head (FIG. 1).
Biochemical compounds that are produced by the various glandular trichomes in tomato comprise terpenoids, flavonoids, fatty acids, alkaloids, and acyl sugars such as acyl glucoses and acyl sucroses. A substance such as chlorophyll however is not among the compounds known to be produced or secreted by glandular hairs in tomato. The produced compounds are known to play important roles in attracting and repelling various insects and in determining susceptibility to certain diseases. However, many aspects of the roles of these metabolites are still unclear, and extensive research is ongoing to determine more precisely the functionality of glandular trichomes and the substances they excrete.
In addition, data on the distribution of which substances are produced by what type of glandular hairs is rather limited and requires specialized approaches to obtain. For many substances it is assumed that they are or may be produced by several glandular hair types, although it is indicated that there are differences in the quality and quantities that are produced by a certain type of glandular hairs. It is for instance known that acyl sugars, which play a significant role in insect resistance, are mainly produced in tomato type I and IV trichomes.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.